Arrangements having IC voltage and thermal resistance designated on a per IC basis

ABSTRACT

Arrangements having integrated circuit (IC) voltage and thermal resistance designated on a per IC basis.

This is a Divisional application of Ser. No. 10/278,021 filed Oct. 23,2002, which is presently pending.

FIELD

Embodiments of the present invention relate to arrangements havingintegrated circuit (IC) voltage and thermal resistance designated on aper IC basis.

BACKGROUND

Background and example embodiments may be described using the context ofprocessor IC die, chips, packages and systems, but practice of thepresent invention and a scope of the claims are not limited thereto.

In order to remain competitive in the marketplace, yields ofsemiconductor IC batches must continue to be improved. Improvements mustalso keep in mind that any overhead/work imposed on subsequentdownstream consumers of the ICs must also be minimized or maintainedwithin reasonable limits, in order to gain wide spread acceptance of theICs.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention will become apparentfrom the following detailed description of example embodiments and theclaims when read in connection with the accompanying drawings, allforming a part of the disclosure of this invention. While the followingwritten and illustrated disclosure focuses on disclosing exampleembodiments of the invention, it should be clearly understood that thesame is by way of illustration and example only and that the inventionis not limited thereto. The spirit and scope of the present inventionare limited only by the terms of the appended claims.

The following represents brief descriptions of the drawings, wherein:

FIG. 1 is an example background (disadvantageous) testing flow and yieldarrangement useful in gaining a more thorough understanding/appreciationof the present invention;

FIGS. 2–4 are first through third example (advantageous) testing flowand yield arrangements (embodiments) useful in gaining a more thoroughunderstanding/appreciation of the present invention;

FIG. 5 is an example processor system embodiment useful in gaining amore thorough understanding/appreciation of further features ofembodiments of the present invention; and

FIG. 6 is an example (advantageous) testing flow arrangement(embodiment) useful in gaining a more thoroughunderstanding/appreciation of the present invention.

DETAILED DESCRIPTION

Before beginning a detailed description of the subject invention,mention of the following is in order. When appropriate, like referencenumerals and characters may be used to designate identical,corresponding or similar components in differing figure drawings.Further, in the detailed description to follow, examplesizes/models/values/ranges/yields may be given, although the presentinvention is not limited to the same. Well-known power/groundconnections to ICs and other components may not be shown within theFIGS. for simplicity of illustration and discussion, and so as not toobscure the invention. Further, arrangements may be shown in blockdiagram form in order to avoid obscuring the invention, and also in viewof the fact that specifics with respect to implementation of such blockdiagram arrangements are highly dependent upon the manufacturing, ICand/or testing platform within which the present invention is to beimplemented, i.e., such specifics should be well within purview of oneskilled in the art. Where specific details (e.g., circuits, flowcharts)are set forth in order to describe example embodiments of the invention,it should be apparent to one skilled in the art that the invention canbe practiced without, or with variation of, these specific details.Finally, it should be apparent that differing combinations of hardwareand software instructions can be used to implement embodiments of thepresent invention, i.e., the present invention is not limited to anyspecific combination of hardware and software.

Again, although disadvantageous and advantageous arrangements may bedescribed using the context of processor IC die, chips, packages andsystems, practice of the present invention and a scope of the claims arenot limited thereto. That is, embodiments of the present invention maybe equally applied in testing and yield improvement of othernon-processor types of IC die, chips, packages, systems, etc.

Turning first to FIG. 1, FIG. 1 is an example background(disadvantageous) testing flow and yield arrangement 100 useful ingaining a more thorough understanding/appreciation of the presentinvention. More particularly, shown is a batch 105 of semiconductor ICs,for example, processor ICs. The term ICs is used generically in thepresent disclosure and claims to broadly mean semiconductor items thatare at any of differing stages of manufacture, e.g., partially processeddie stage, at a pre-packaging die stage, or at a post-packaging (chip)stage. A given batch may include hundreds, millions, and even tens orhundreds of millions of ICs.

Such batch may have been manufactured by the same entity (e.g.,individual, partnership, corporation, etc.) that will perform subsequenttesting (sometimes called “testing entity” or “tester”, hereinafter), oralternatively may have been manufactured by a differing entity andobtained (e.g., purchased for redistribution) by the tester. The testingentity may perform testing in an attempt to guarantee a quality of theindividual ICs, while at the same time trying to maximizesaleable/useable yields of the batch 105.

Testing may be performed automatically (as opposed to manually), forexample, by automated testing setups/machines. Testing of the ICs may beperformed sequentially, in parallel, etc.

In anticipation of testing, the tester may set up a plurality of binssuch as the FIG. 1 designated BIN1, BIN2, B1N3, BIN4, BIN5, DISCARDbins. While the FIG. 1 (and FIGS. 2–4) example(s) of the presentdisclosure utilizes five (5) example bins, practice of embodiments ofthe present invention broadly encompasses any number of bins. The binsmay be set-up/partitioned/designated on a basis of any number ofdifferent parameters, and in the present FIG. 1 example, the variousbins have been set up on a basis of reliable operational frequencies atwhich the ICs are capable of operating.

That is, the FIG. 1 (and FIGS. 2–3) example BIN1, BIN2, BIN3, BIN4, BIN5bins have been set-up to receive ICs capable of being reliably operatedat 1.9 GHz, 1.8 GHz, 1.7 GHz, 1.6 GHz and 1.5 GHz frequencies,respectively. Again, practice of embodiments of the present invention isnot limited to such example frequencies. As a general rule, ICsoperating at the highest frequency may be able to be sold for a highercommercial price than lower frequency ICs, and accordingly, the BIN1,BIN2, BIN3, BIN4, BIN5 bins of the present example have been arranged inan order of highest commercial value to lowest value from left to right.

Of course, the DISCARD bin is set up to receive ICs that are considerednon-operational due to breakage, untestability, or testing failures, andhence the DISCARD bin has the FIG. 1 operational frequency designationof N/A (not applicable). ICs that are designated for or sent to theDISCARD bin are disadvantageously considered (for discussions of thepresent FIG. 1 example) to be of little or no value.

In further preparation of testing, testing guidelines/parameters may bedetermined for the batch to guide or set benchmarks for testing. Asnon-limiting/non-exhaustive examples, target voltage and power spec(i.e., specification) parameters may have been determined for the FIG. 1example, such being shown representatively by the FIG. 1 block 115.

In the FIG. 1 example, the predetermined target voltage is consistentlyapplied (without variation) to each and every testable IC, to determinewhether that IC can operate properly at the target (i.e., expected Vcc)voltage. Testing respective ICs of a batch at differing (i.e., varying)target voltages (e.g., 1.75V, 1.725V, 1.70V, etc.) was not used/appliedwith the FIG. 1 testing arrangement, mainly because it is felt thattesting respective ICs at numerous target voltages would requireexcessive testing time (thus slowing manufacturing, testing and deliveryof the ICs to market), and further, it was felt that downstream userswould not have accepted an IC inventory requiring mixed-voltages whichin turn would have required an inventory of differing voltage supplies.

Turning next to determination of the exact target voltage that should beapplied, the target voltage may be determined in any number of differentways. However, since a substantial portion of any IC's internaldesign/workings typically is maintained as a trade secret, determinationof an appropriate testing target voltage is most easily/appropriatelydeterminable by those skilled in the art who are most intimatelyinvolved with the internal design/workings of that IC, and is wellwithin the purview of such skilled artisans.

As non-limiting/non-exhaustive examples, the target voltage may be acore voltage (Vcc) expected to be applied to the ICs during ultimate usethereof, and accordingly, the expected Vcc may be used as the testingvoltage during testing. That is, the ICs may be designed and/ormanufactured to operate at an expected core voltage (Vcc), andaccordingly, the target voltage may be predetermined by the design atthe design stage. Such expected target voltage may then be supplied bythe designer, manufacturer and/or supplier of the untested (raw) ICbatch 105 to the tester. Alternatively, the tester may perform somepre-testing of a small sampling of the untested ICs, and use the resultsfrom the pre-testing to determine/designate a target voltage which isexpected to result in satisfactory batch testing and a satisfactory(PASS) yield.

One example target voltage is 1.75V, and such example voltage is adoptedas the testing target voltage for the present FIG. 1 example. However,practice of embodiments of the present invention is not limited to suchspecific target voltage, or to having the target (testing) voltageexactly match the core (Vcc) voltage.

Turning next to determination of the target power spec, the power specmay be determined in any number of different ways. Any number ofdiffering parameters and/or ranges may be set, depending upon manyspecifics such as the type of IC being tested, the environment in whichthe IC is to be implemented (e.g., consumer products, automotive, space,etc.), testing inputs/outputs available on the ICs, cooling arrangementswhich would be available within the marketplace for use with the IC,etc. Since a substantial portion of any IC's internal design/workingstypically is maintained as a trade secret, determination of anappropriate testing power spec is most easily/appropriately determinableby those skilled in the art who are most intimately involved with theinternal design/workings of that IC, and is well within the purview ofsuch skilled artisans.

As a non-limiting/non-exhaustive example, the untested ICs may have beendesigned and/or manufactured to operate within a specific(predetermined) power spec, and accordingly, the power spec may bepredetermined by the design at the design stage, and then supplied bythe designer, manufacturer and/or supplier of the untested (raw) ICbatch 105 to the tester. Alternatively, the tester may perform somepre-testing of a small sampling of the untested ICs, and use the resultsfrom the pre-testing to determine/designate a power spec which isexpected to result in satisfactory batch testing and a satisfactory(PASS) yield.

For the FIG. 1 (and FIGS. 2–3) example(s), testing will look at, forexample, a static (clock off) power, dynamic (clock on) power, and total(combination of static and dynamic) power. Again, practice ofembodiments of the present invention is not limited to such examplepower spec and/or power measurements/types. An acceptable range may beset for each of these power types, and if an IC displays a power withinthe ranges during testing at the target voltage, then the IC may beconsidered a “PASS” for the given target voltage and power spec.Alternatively, if outside of range on any one of these power typesduring testing at the target voltage, then the IC may be considered a“FAIL”.

Discussion continues with further description of the FIG. 1 exampletesting operation. As an initial note, even before testing is conducted,a certain portion 106 of the batch may be found (e.g., via physicalinspection or scanning) unuseable/untestable at the onset, and may bedesignated for or sent to the DISCARD bin before testing (shownrepresentatively by the short-dashed-line arrow 110). In the FIG. 1example, this may represent, for example, 0.2% of the batch, and may bedue to IC breakage or other types of mechanical defects.

A portion, majority or even an entire testable remainder (designated bythe arrow 120) of hundreds, millions, and even tens or hundreds ofmillions of ICs of the batch 105 may then be subjected to testing at thetarget voltage and target power spec 115 at block 125. That is, at block125, the actual testing is applied (e.g., at a suitable testerstation/machine). A very large number of possible testing sequences maybe able to be applied to each IC, even with the given target voltage andpower spec. However, for sake of brevity and clarity, the FIG. 6 exampletesting sequence is assumed applied to the FIG. 1 (and FIGS. 2–4)example(s). Practice of embodiments of the present invention is notlimited to such example testing sequence.

FIG. 6 is an example (advantageous) testing flow arrangement(embodiment) 600 useful in gaining a more thoroughunderstanding/appreciation of the present invention. More particularly,within testing flow 610, first a present target voltage and spec (here apower spec) is loaded (block 620) into an automated testing apparatus.Next, testing of each subject IC is conducted at each testing frequencyof interest (blocks 630–690). In the FIG. 6 example testing flow, it isassumed that each IC will be tested (block 630) first at the highestpossible bin frequency (i.e., 1.9 GHz), and if necessary, retested atlower (block 640) and lower (blocks 650–690) bin (step) frequencies(shown representatively by the rightward N arrows) up until the ICachieves a PASS. Upon a pass, testing for that IC is finished, and thepassed IC is distributed to the appropriate bin (shown representativelyin FIG. 6 by the downward arrows from blocks 630–690, andrepresentatively in FIGS. 1–4 by an IC being positioned over a bin).That is, if at any given time, a FIG. 1 IC receives a PASS, testing withrespect to that IC may be considered completed, whereupon the IC can beimmediately designated for or sent to the appropriate bin (i.e., withouttesting at any other lower frequency steps). Such helps to minimize anoverall testing time needed to test the entire batch.

It is important to understand that any given IC may be able to PASS at aplurality of bin frequencies, e.g., an IC that passes at 1.8 GHz mayalso be able to pass at 1.7 GHz, 1.6 GHz and 1.5 GHz. The FIG. 1arrangement of testing from highest to lowest frequency steps anddistributing an IC upon first PASS, is advantageous in that it tends topass/distribute an IC into its highest frequency (most commerciallyvaluable) bin. Such arrangement tends to maximize a profit for thebatch.

To initiate testing, the target voltage is applied to the IC. After apredetermined time (e.g., to allow the IC under test to stabilizethermally, electrically, etc.), the ICs' static (clock off) power istested (at applicable ones of the differing frequency test blocks630–690) to see whether it is within power spec range. In addition, thedynamic (clock on) power and/or total (combination of static anddynamic) power may also be tested at the subject frequency to seewhether they are also within range. If the IC displays power readingswithin the ranges during testing at the subject 1.9 GHz, then the IC maybe considered a “PASS” (shown representatively by the FIG. 1 solid linearrow 150) for the given target voltage and power spec, and that IC isdesignated for or sent to BIN1 (shown representatively by the solid linearrow 151).

Alternatively, if outside of range during testing at 1.9 GHz and at thetarget voltage, then the testing frequency may be reset to the nextpossible bin frequency (block 640), i.e., 1.8 GHz, and the IC retested.Again, if the IC displays a power within the power spec ranges duringtesting at 1.8 GHz, then the IC may be considered a “PASS” (shownrepresentatively by the solid line arrow 150) for the given targetvoltage and power spec, and that IC is designated for or sent to BIN2(shown representatively by the solid line arrow 152). If outside ofrange, retesting may be subsequently done at each of the lower-and-lower1.7 GHz, 1.6 GHz, 1.5 GHz test frequencies (blocks 650–680) hoping for a“PASS”, with any IC actually passing at 1.7 GHz, 1.6 GHz, 1.5 GHz beingdesignated for or sent to the BIN3, BIN4, BIN5 bins, respectively (asshown representatively by the solid line arrows 153, 154, 155,respectively).

Alternatively, if outside of range during testing at the target voltageand all of the testing frequencies, then the IC may be considered a“FAIL”, and may be destined for or sent to the DISCARD bin (shownrepresentatively by the short-dashed-line arrow 130).

At the conclusion of testing, there may be a bin split distribution ofthe ICs for the bins, with the FIG. 1 example showing exampledistributions given within parenthesis at the bottom of such FIG., i.e.,BIN1 (1.5%), BIN2 (24.0%), BIN3 (48.2%), BIN4 (21.8%), BIN5 (2.0%),DISCARD (2.5%). That is, with the present FIG. 1 example, as shown inparentheses to the left of the IC row, a total of 97/5% of the ICs endedup in or designated for the useable bin. It can be seen that a majorityof the successfully tested ICs ended up in the BIN2, BIN3, BIN4 bins,with a highest concentration thereof being 48.2% distributed in BIN3.Further note that a total of 2.5% of the ICs ended up in the DISCARD binand are considered (for purposes of the FIG. 1 example) disadvantageouswaste.

That is, such damaged/failed ICs do not contribute to the yield derivedfrom the batch 105, and may represent an economic loss. With the FIG. 1example disadvantageous arrangement, the 2.5% discard was relatively lowand was taken as an acceptable loss. Further, a perception associatedwith such FIG. 1 disadvantageous arrangement was that it would not beworth the time/cost to attempt salvage any of the discard ICs.

Returning discussion back to the successfully passed ICs, at some pointin time (e.g., at the time of testing, or at a time downstream from thetesting), each IC within a respective bin (of the FIGS. 1–4 examples)may receive appropriate descriptive and/or spec markings commensuratewith the manufacturing thereof and the testing results. For example,directing attention and using the FIG. 1 IC 107 as an example, such ICmay have, for example, five lines of information marked thereon.

A first line reading “XYZ-PROC” may designate the IC as a processor ICthat is being distributed by the XYZ Corporation. A second line reading“1.9 GHz/256/400” may designate the processor as being reliably operableat processor speeds of up to 1.9 GHz, as having 256 Kbytes of internalcache memory, and as being reliably operable with bus speeds of up to400 MHz. A third line reading “1.75V/73C” may designate that the IC isdesignated for use with 1.75 volt voltage supply, and a temperature ofup to 73 degrees Celsius (to ensure correct and reliable thermaloperation of the IC). A third line reading “A-B001001” may designatethat the IC was produced at manufacturing plant A, and as part of batch(B) no. 001001. Finally, the last line reading “SNXXXXX” may designate aserial number of the IC. Practice of embodiments of the presentinvention is not limited to five lines of information, and is notlimited to the above example descriptive and/or spec markings.

Of importance to note in FIG. 1, the second information line of the ICswithin the differing bins are marked with differing reliable processorspeeds. Further, note also that all of the ICs within the BIN1, BIN2,BIN3, BIN4, BIN5 bins are commonly marked with the same “1.75V” voltagedesignation.

A disadvantage of the FIG. 1 arrangement is that, while an acceptableyield may be achieved, the inventors of the present invention haveperformed significant research/analysis and have recognized thatalternative testing arrangements applied to test the same manufacturingbatch, may significantly improve yield, profit, etc. thereof. Moreparticularly, the inventors have found that the FIG. 1 arrangement isdisadvantageous in that it applies target voltage testing at only asingle target voltage (i.e., a coarse granularity).

In their research/analysis, the inventors came to the conclusion thatICs (e.g., processor ICs) behave according to the following generalizedpower, reliability and performance equations:Fmax=f(Vcc, Temp, V _(t) ,L _(min))  (Eq. 1)Power=f(Vcc, Temp, V _(t) , L _(min))  (Eq. 2)Rel=f(Vcc, Temp, V _(t) ,L _(min))  (Eq. 3)T _(j) =T _(a)+θ_(j) P  (Eq. 4)Power Delivery Impedance=(VID−V)/I=Z  (Eq. 5)where: F is an operational frequency of the IC; f is a function; Vcc isa core voltage of the IC; V_(t) is a threshold voltage of the on-ICtransistors; L_(min) is a gate length of the transistors of the IC; Relis a reliability of the IC; T_(j) is silicon junction temperature of theIC; T_(a) is the ambient (system) temperature; θ_(j) is the thermalresistance at the silicon junction of the IC; P is power; VID is avoltage defined by a voltage identification arrangement internally inthe IC; V is voltage; I is electrical current; and Z is electricalimpedance from the voltage regulator to the IC.

The above example equations represent generalized equations applicableto most (if not all) ICs. As to specific equations applicable to aspecific IC, since a substantial portion of any ICs' internaldesign/workings typically is maintained as a trade secret, determinationof exact or approximation equations is most easily/appropriatelydeterminable by those skilled in the art who are most intimatelyinvolved with the internal design/workings of that IC, and is wellwithin the purview of such skilled artisans.

In turning now to apply the equations to further understanding of thepresent invention, since the present FIG. 1 example tests and splits thebins according to frequency, the present discussion will focus on thefrequency Eq. 1. More particularly, Eq. 1 states that (at minimum) Fmax(i.e., a maximum operating frequency of an IC) is a function of Vcc,Temp, V_(t), and L_(min).

Of these four variables, V_(t) and L_(min.) may be more adjustableduring die design and manufacturing (i.e., semiconductor processing)stages, rather than at the testing stage. Further, Temp may be directlyrelated to the frequency at which the IC is operated (i.e., higherfrequencies generally producing a higher Temp). Accordingly, on a basisof the foregoing, the inventors recognized Vcc as a variable that may bemost easily changeable/settable at the testing stage toinfluence/improve the testability (passing) and maximum operatingfrequency Fmax of an IC. Relatedly, the inventors noted that Vcc mayalso be the most easily changeable and settable variable within theother power and reliability equations (Eqs. 2 and 3) as well.Accordingly, Vcc will be used as the variable of interest in thediscussions and example testing embodiments to follow.

More particularly, testing was performed on wasted ICs from the FIG. 1DISCARD bin, to determine whether a change in the testing target voltage(i.e., Vcc) could be used to redeem any of the DISCARD ICs. That is,FIG. 2 is a first example (advantageous) testing flow and yieldarrangement (embodiment) 200 useful in gaining a more thoroughunderstanding/appreciation of the present invention. For consistency andease of comparison, FIG. 2 maintains the same FIG. 1 example bins.

As a first difference from FIG. 1, in addition to the single (original)testing target voltage, additional predetermined testing voltage levelsteps may be determined which might be appropriate to apply to retestones of the FIG. 1 DISCARD ICs. Determination of a range of voltagesteps is shown representatively within FIG. 2 by block 135. Again, sincea substantial portion of the IC's internal design/workings typically ismaintained as a trade secret, determination of appropriate step targetvoltages is most easily/appropriately determinable by those skilled inthe art who are most intimately involved with the internaldesign/workings of that IC, and is well within the purview of suchskilled artisans. In the present FIG. 2 (and FIGS. 3–4) example(s), itwas determined that it was appropriate to apply 25 mV steps, i.e., dropfrom the original 1.75V to step down to 1.725V, then 1.70V, etc., andfinally ending testing at a 1.50V step. Again, practice of embodimentsof the present invention is not limited to such example voltage stepgranularity, or the above specific voltage steps or range of steps.

It should also be noted that testing with the present FIG. 2 examplerequired a differing respective power spec for each respective steptarget voltage. That is, as one example, a different testing power specwas applicable to ICs being tested at 1.725V as opposed to 1.75V. Forexample, ICs being operated at 1.725V will have a different viablestatic power range, dynamic power range, etc., than that being operatedat 1.75V. Again, since a substantial portion of any IC's internaldesign/workings typically is maintained as a trade secret, determinationof appropriate respective power specs associated with each of the steptarget voltages is most easily/appropriately determinable by thoseskilled in the art who are most intimately involved with the internaldesign/workings of that IC, and is well within the purview of suchskilled artisans.

In the present FIG. 2 example, each of the different testing power specsagain concerned static (clock off) power, dynamic (clock on) power,total (combination of static and dynamic) power, etc, with acceptableranges being set for each of these power specs. If a DISCARD IC beingtested at a step target voltage displays a power within the ranges ofits corresponding power spec, then the IC may be considered a “PASS” forthe given step target voltage and power spec. Alternatively, if outsideof range during testing, then the IC may be considered a “FAIL”.

Accordingly, continuing discussion of the FIG. 2 example, items similarto those of the FIG. 1 example are labeled with the same referencenumerals, and redundant discussion thereof is omitted for sake ofbrevity. In addition to testing block 125 and its corresponding binsplit flows to the BIN1, BIN2, BIN3, BIN4, BIN5 bins (shownrepresentatively by the arrows 150–155), the FIG. 2 example hasadditional testing blocks 140–149, with their corresponding bin splitflows (shown representatively by the arrows 160–165, 170–. . . and190–195, respectively). The number of testing blocks may be any number(shown representatively by splice 142–148), and, for example, maycorrespond to a number of testing voltage level steps.

Previously passed ICs from FIG. 1 were not retested, and instead areshown in the top FIG. 2 IC row designated 1.75V (97.5%). Furtherhorizontal rows of ICs have been provided below this top row and abovethe BIN1, BIN2, BIN3, BIN4, BIN5 and DISCARD bins, to further receiveretested DISCARD ICs which may be subsequently found to PASS withtesting at the additional step (Vcc) voltages. Such additional rows havebeen designated along a left-hand side of FIG. 2 as 1.725V, . . . ,1.50V.

In the retesting operation, DISCARD ICs from the FIG. 1 DISCARD bin werethus retrieved and applied (shown representatively by the dashed linearrow 130″) to the additional testing blocks 140–149. Alternatively,rather than being discarded directly from the testing block 125 (shownrepresentatively by the dashed line 130) and subsequently retrieved(shown representatively by the dashed line arrow 130″), unpassed ICsfrom the testing block 125 may be directly routed (shownrepresentatively by the sold line arrow 130′) from the testing block 125to the additional testing blocks 140–149.

The same frequency step testing (FIG. 6) as was done with the testingblock 125 is similarly performed for each of the additional testingblocks 140–149, except that the new voltage steps and theircorresponding power specs are respectively applied. More particularly,in the FIG. 2 example, it is assumed that for testing block 140, an ICwill be first tested at the highest possible bin frequency, i.e., 1.9GHz. To initiate testing, the applicable step target voltage is appliedto the IC (FIG. 6 block 630), and after a predetermined time (e.g., toallow the IC under test to stabilize thermally, electrically, etc.), theICs' static (clock off) power is tested to see whether it reads withinthe corresponding power spec range. Subsequently, the dynamic (clock on)power and/or total (combination of static and dynamic) power may also betested to see whether they are within range. If the IC displays a powerwithin range during testing at 1.9 GHz and at the step target voltage,then the IC may be considered a “PASS” (shown representatively by theFIG. 2 long-/short-dashed arrow 160) for the given step target voltageand power spec. That IC may thus be designated for or sent to BIN1(shown representatively by the long-/short-dashed arrow 161).

Alternatively, if outside of range during testing at 1.9 GHz and at thestep target voltage, then the testing frequency may be reset to the nextpossible bin frequency, i.e., 1.8 GHz (FIG. 6 block 640), and the ICretested. Again, if the IC displays a power within the power spec rangesduring testing at 1.8 GHz and at the step target voltage, then the ICmay be considered a “PASS” (shown representatively by thelong-/short-dashed arrow 160) for the given step target voltage andpower spec, and thus be designated for or sent to BIN2 (shownrepresentatively by the long-/short-dashed arrow 162). If outside ofrange, retesting may be subsequently done at each of the lower-and-lower1.7 GHz, 1.6 GHz, 1.5 GHz test frequencies (FIG. 6 block 650 f) hopingfor a “PASS”, with any ICs passing at 1.7 GHz, 1.6 GHz, 1.5 GHz beingdesignated for or sent to the BIN3, BIN4, BIN5 bins, respectively (asshown representatively by the long-/short-dashed arrows 163, 164, 165,respectively).

If an IC fails to pass for the block 140 step voltage testing, retestingmay be subsequently done at each of the lower-and-lower 2^(nd), 3^(rd),nth step voltages/power-specs with the testing blocks 141–149, with allof the 1.9 GHz–1.5 GHz test frequencies being applied at each decreasingstep voltage, until a PASS is encountered. Passes from block 141 testingare shown, for example, representatively by pass output 170 (with bindistribution arrows thereof not being shown so as to avoid crowding),and passes from block 149 testing are shown, for example,representatively by the long-/multi-short dashed line 190–195.

At conclusion of testing, the retested ICs that have passed as a resultof block 140, are shown as being arranged within a 1.725V row, and theretested ICs which have passed as a result of block 149, are shown asbeing arranged within a 1.50V row. Rows and ICs that were intermediateto these two 1.725V and 1.50V rows were not illustrated for sake ofbrevity/clarity. The percentage distribution of ICs within each row isshown in parenthesis along a left-hand side of each row. Note that 97.5%of the ICs which had previously passed via the FIGS. 1–2 testing block125 at the 1.75V testing voltage are congregated within the 1.75V row,whereas the 2.1% of reclaimed DISCARD ICs are distributed within theother 1.725V, . . . 0.1.50 rows.

It should be noted at this point that it is not required that each andevery one of the testing blocks 125 and 140–149 result in distributionof ICs therefrom to each and every one of the BIN1, BIN2, BIN3, BIN4,BIN5 bins. That is, any given testing block 125 and 140–149 may resultin distribution to fewer than all of the bins, and may even result indistribution to none of the bins (for example, in a case where allretested ICs fail). To state it succinctly, the resultant bindistribution from any testing block is totally dependent on the PASSINGof the tested ICs therefrom.

Continuing discussion, for any of the FIG. 2 retested ICs which is foundto be outside of power spec range during testing at all of the steptarget voltages and all of the testing frequencies, then the IC may beconsidered a “FAIL”. FAILED ICs may be designated for or sent to theDISCARD bin (shown representatively by the short-dashed-line arrow 199).Note that 0.4% of the total ICs still ended up in the DISCARD bin evenafter retesting, i.e., 0.2% represents the original untestable ICs(arrow 110), and 0.2% represents ICs that FAILED even upon the FIG. 2retesting.

At the conclusion of testing, there may be an example bin splitdistribution of the ICs within the bins as shown in parenthesis at thebottom of FIG. 2. That is, while the FIG. 1 example had shown exampledistributions of: BIN1 (1.5%), BIN2 (24.0%), BIN3 (48.2%), BIN4 (21.8%),BIN5 (2.0%), DISCARD (2.5%), FIG. 2 shows significantly improvedyield/distributions of BIN1 (2.3%), BIN2 (24.6%), BIN3 (48.7%), BIN4(21.9%), BIN5 (2.1%), DISCARD (0.4%). That is, 2.1% of the original 2.5%DISCARD ICs have been reclaimed using the FIG. 2 example testingarrangement, with this reclaimed 2.1% of ICs being distributed asfollows: BIN1 (+0.8%), BIN2 (+0.6%), BIN3 (+0.5%), BIN4 (+0.1%), BIN5(+0.1%).

As it may be important to further understanding and appreciation of theinvention, remember that it was previously stated that ICs operating atthe highest frequency may be able to be sold for a higher commercialprice than lower frequency ICs, and that the BIN1, BIN2, BIN3, BIN4,BIN5 bins have been arranged in an order of highest commercial value tolowest value from left to right. Accordingly, perhaps the mostsignificant aspect to realize from the FIG. 2 example is that while allof the reclaimed 2.1% ICs represent increased yield/profit, a 1.4%majority of the reclaimed ICs end up reclaimed into the mostvaluable/profitable BIN1 and BIN2 bins. This is important and veryadvantageous because it may be very difficult to manufacture/achieve ICsthat are operable at the BIN1 and BIN2 frequencies. With the presentinvention, in essence previous waste ICs have been reclaimed as ones ofthese difficult-to-achieve ICs, and have been turned into significantadditional profits, simply by applying testing at additional lowertesting voltage steps. That is, the previous low discard (2.5%) that waspreviously viewed as acceptable (with FIG. 1), may in fact contain someof the most valuable ICs within the batch.

Once the FIG. 2 testing has been completed, at some point in time (e.g.,at the time of testing, or at a time downstream from the testing), eachIC within a respective bin may receive appropriate descriptive and/orspec markings commensurate with the manufacturing thereof and thetesting results. For sake of brevity, the FIG. 2 (and FIGS. 3–4) passedICs are marked with similar information as that of the FIG. 1 ICs havingfive lines of information marked thereon. However, as one importantdifference, note that while the FIG. 1 ICs are all commonlymarked/destined for operation at 1.75V (i.e., Vcc), the FIG. 2 (andFIGS. 3–4) ICs are diversely marked/destined for operation at a numberof differing voltages, i.e., some ICs are designated to be operated atthe original 1.75V, some at 1.725V, some at 1.70V, etc., all the waydown to the example 1.50V. The greater the granularity of testingvoltage steps, the more diversely the ICs inventory will be marked.

As another important difference, note that the FIG. 2 (and FIGS. 3–4)ICs are no longer marked with a designated temperature, but instead, aremarked with a thermal resistance (or impedance) “T” value. That is, athird line may instead, for example, be marked to read “1.725V/0.7T”which may designate that the IC is designated for use with 1.725 voltvoltage supply, and any cooling arrangement/design (e.g., heat sink)used in conjunction with the IC should take into consideration that theIC is designated with a 0.7 thermal resistance. The thermal resistanceis also sometimes referred to as “θ_(ja)”, where θ_(ja) is the thermalresistance of the thermal path between the silicon junction of the ICand the ambient environment (e.g., air) surrounding the IC.Research/analysis leading to the present invention had shown that thereis one optimal (Vcc, Temp, V_(t), L_(min)) that maximizes performancefor a given cost (θ_(ja)), and accordingly, it appeared appropriate todesignate thermal resistance as T or θ_(ja) (rather than temperature)with the designated optimal Vcc.

One potential disadvantage of the FIG. 2 and other (FIGS. 3–4)embodiments (discussed ahead) is that a diverse or elaborate inventoryof ICs designated for differing Vcc voltages may (if not managedproperly) impose additional overhead/work on downstream consumers of theICs (e.g., original equipment manufacturers (OEMs)). More particularly,as mentioned previously, any overhead/work imposed on subsequentdownstream consumers of the improved yield ICs must be minimized ormaintained within reasonable limits in order to gain wide spreadacceptance of the ICs. For example, if the OEMs were faced withobtaining and maintaining an elaborate/diverse/expensive inventory ofdiverse voltage/power supplies which mirrored the diverse voltage (Vcc)requirements of the differing ICs, then the OEMs may very wellshun/avoid the ICs, thereby preventing widespread acceptance of thesame.

However, a solution which avoids this potential problem is available, inthat automatically adjustable voltage regulator modules (VRMs) haverecently gained popularity in the industry. More particularly, a VRM maybe a DC-DC converter that automatically senses voltage designationinformation from the IC, and on a basis of the sensed information,automatically supplies the correct voltage and current to the IC withoutany further intervention required of the OEM. The ICs of the presentinvention may be used with VRMs. Thus, the OEM may be able toobtain/maintain only a single inventory of adjustable VRMs, rather thana diverse inventory of voltage/power supplies, and hence theabove-mentioned potential disadvantage of the present invention isminimized.

As to particulars of implementing a VRM with an IC of the presentinvention, there is a plurality of different ways in which the VRM mightbe able to automatically sense the voltage designation information. Moreparticularly, attention is momentarily directed to FIG. 5 which is anexample processor system embodiment 500 useful in gaining a morethorough understanding/appreciation of further features of embodimentsof the present invention. Shown is an example processor enabled system505 having one or more processors 510 which may be part of a processorpackage 520 that may include a VRM 530. The system 505 may furtherinclude a printed circuit board (PCB) 540 (for example, a motherboard),a connector 550 and an input/output device 560.

As a first example of a way to implement the VRM, each IC which achievesa pass upon testing may have an internal voltage identification (VID)arrangement electrically set (e.g., via blowing of appropriate internalelectrical fuses) so as to contain an internal electrical designation ofits designated Vcc voltage. Thus, a Vcc voltage designated for deliveryto the IC would be selected by the value encoded on the VID arrangementand readable via pin connections of the IC. Alternatively, a designatedVcc voltage may instead be programmed with package routing, but routingis more difficult to implement than fusing. At the end of testing andVID programming, same line item parts from a same stepping (batch) and asame frequency would then have different VID settings fused or routedtherein. That is, each IC would have internal preprogramming to have VCCselected by the encoded VID value.

The VRM then might be able to automatically sense the VID by beingelectrically connected to the processor 510 by a plurality of voltageidentification (VID) electrical lines (shown representatively by theFIG. 5 arrow 591), and by being able to sense/read a combination ofopens/shorts on such lines. For example there may be five (5) VID lines,and various combinations of 1's and 0's on the lines may designate theappropriate Vcc voltage for the IC. As one example, “00101” maydesignate the 1.725V required by the FIG. 5 example processor 510.

As another alternative to sense voltage designation information, the VRMmay be equipped with an optical and/or magnetic scanning arrangement,wherein the VRM is able to automatically scan (shown representatively bythe FIG. 5 arrow 592) the voltage designation information written on anoutside of the IC (e.g., in reflective ink, magnetic ink, etc.). Thatis, external readable information may be written as readable graphical(e.g., alphanumeric) characters, symbols, bar coded information, etc. Asanother example, the VRM might be equipped to receive/readelectromagnetic transmission information (shown representatively by theFIG. 5 lightning bolt 593) transmitted from a nominally powered IC.

As still a further alternative, the voltage designation information maybe able to be stored/retrieved remotely from the IC. More particularly,FIG. 5 further shows a remote database 580 (e.g., maintained at the IC'soutsourcing XYZ Corporation) which may contain a table whichcross-references IC serial numbers to corresponding voltage designation(and other) information. Accordingly, the database 580 may contain entry581 containing information corresponding to the processor 510, i.e., asan example, FIG. 5 illustrates this entry 581 as containing theinformation “SNXXXXX 1.725V/0.7T”.

To sense such remote entry 581, the processor enabled system 505 may beconstructed to first power up nominally from the VRM using apredetermined safe nominal voltage sufficient to make the system atleast marginally operable, and thereafter, the VRM 530 and/or processor510 may retrieve (shown representatively by the FIG. 5 two-headed arrow594) using a communication/download 570 via communications 571, 172. Oneexample would be retrieving such information via an Internet download.Once the voltage designation information has been remotely retrieved,the VRM 530 may thereafter automatically fully power up the processor510 from the nominal voltage up to the proper designated voltage (i.e.,Vcc).

As to the industry acceptance of the change in the on-IC designation ofthermal resistance instead of temperature, it is felt that theadjustment to thermal resistance designations represents little orreasonable overhead/work imposed on subsequent downstream consumers(e.g., OEMs), and accordingly, should not be an impediment to widespread acceptance of such ICs.

Another potential disadvantage of the FIG. 2 and other embodiments(discussed ahead) is that additional testing time is required. However,one example estimate has found the step testing would only take 100 msecper IC unit per iteration. Such was felt reasonable/acceptable testingpenalty, especially in view of significant return value/profit resultantfrom reclaiming ICs to valued bins.

Discussion turns next to another example embodiment of the presentinvention. More particularly, FIG. 3 is a second example (advantageous)testing flow and yield arrangement (embodiment) 300 useful in gainingfurther understanding/appreciation of the present invention. While theFIG. 2 example embodiment focuses on simply reclaiming discarded ICs,the FIG. 3 example embodiment focuses on applying the step targetvoltage testing to all ICs (i.e., each and every IC) in an attempt tofurther improve yield, profit, etc. Thus, the FIG. 3 arrangementproposes to designate a variable (step) voltage and/or thermalresistance on a per IC basis.

More particularly note, in comparing FIG. 2 and FIG. 3, that theoriginal target volt/pwr-spec block 115 and target testing block 125have been instead incorporated into a range (step) volt/pwr-specdetermination block 135′, and that that the plurality of step testingblocks 140′–149′ are used to test each IC of the portion, majority oreven entire testable remainder 120 of the testable ICs of the batch 105.Testing block 140′ results in passes/distributions 390–395, testingblock 148′ results in passes/distributions 370–375, and testing block149′ results in passes/distributions 360–365. Again, for any ICs whichis found to be outside of power spec range during testing at all of thestep target voltages and all of the testing frequencies, then the ICsmay be considered a “FAIL”, and may be designated for or sent to theDISCARD bin (shown representatively by the short-dashed-line arrow 399).

As one important difference, note that while the FIG. 2 examplearrangement was arranged to generally test from the highest possiblestep voltage toward the lowest, the FIG. 3 example arrangementoppositely tests from lowest possible step voltage (block 140′) towardthe highest (block 149′). Such may be further advantageous over the FIG.2 testing from highest to lowest.

More particularly, previously it was mentioned that the BIN1, BIN2,BIN3, BIN4, BIN5 bins of the present example have been arranged in anorder of highest commercial value to lowest value from left column toright, i.e., higher frequency ICs (left column) selling for a higherprice than lower frequency ICs (right columns). This type of commercialvalue analysis can likewise be extended to the operating (Vcc) voltage.

That is, since, as a general rule, ICs operating at lower Vcc voltagesmay be able to be sold for a higher commercial price than ICs operatingat higher Vcc voltages (and at the same frequency), the rows 1.75V,1.725V, . . . , 1.50V of the present example have been arranged in anorder of lowest commercial value at the top 1.75 volt row, to thehighest commercial value at the bottom 1.50V row. Thus, overall withinthe FIG. 3 array of ICs, the lowest and left-most ICs in FIG. 3 ICdistribution array may have the highest commercial value, whereas thehighest and right-most ICs have the lowest commercial value. Thus, agoal to increase profits would be to place/move more ICs toward thelowest, left-most row/bins.

Testing from lowest step voltage to highest is advantageous in that ittends to pass/distribute ICs into the lowest step (Vcc) voltage (i.e.,the most commercially valuable) bins, i.e., testing and binning uponfirst pass is biased to distribute ICs into the lowest (most valuable)row, and left-most (most valuable) bins. That is, if a given IC is ableto pass at plurality of differing step voltages such as 1.725V, 1.70V, .. . , 1.50V, testing this IC at the lowest 1.50V step voltage first andthen ending testing and distributing upon a first PASS, would result inthe IC being designated for or sent to the 1.50V row (as opposed to theother less commercially valuable rows).

At the conclusion of testing, there may be an example bin splitdistribution of the ICs within the bins as shown in parenthesis at thebottom of FIG. 3. That is, while the FIG. 1 example had shown exampledistributions of: BIN1 (1.5%), BIN2 (24.0%), BIN3 (48.2%), BIN4 (21.8%),BIN5 (2.0%), DISCARD (2.5%), and FIG. 2 had shown significantly improvedyield/distributions of BIN1 (2.3%), BIN2 (24.6%), BIN3 (48.7%), BIN4(21.9%), BIN5 (2.1%), DISCARD (0.4%), FIG. 3 shows even furthersignificantly improved bin distributions of BIN1 (6.7%), BIN2 (35.9%),BIN3 (42.1%), BIN4 (14.4%), BIN5 (0.5%), DISCARD (0.4%). Further, whileFIG. 2 showed row distributions of 1.75V (97.5%), 1.725V (1.4%), . . . ,(0.6%), . . . , 1.50V (0.1%), FIG. 3 shows even further significantlyimproved row distributions of 1.75V (88.3%), 1.725V (8.1%), . . . ,(1.6%), . . . , 1.50V (0.6%). That is, whereas the yield (99.6%) stayedthe same from FIG. 2 to FIG. 3, the FIG. 3 testing arrangement moreoptimally redistributed some (ones) of the yield ICs from less valuablerows/bins into lower more valuable rows, and into left-ward morevaluable bins. Hence, an overall profit will have been significantlyimproved.

In addition to an up-front increase in profits, redistributing of ICsfrom higher to lower voltage bins may also result in higher possiblefrequencies (for a given cooling arrangement), or a further increase inprofits downstream. More particularly, as to higher possiblefrequencies, a maximum operating frequency of an IC is often limited bya cooling capacity of an available cooling arrangement (i.e., wherethermal breakdown will occur). If less heat is generated as a result ofa lesser Vcc voltage being applied to an IC, then additional (unused)cooling capacity becomes available for other uses. As one example, theadditional (i.e., regained) cooling capacity may be able to be used toincrease the IC's operational frequency (which typically causesincreased heat generation). That is, because less voltage watts have tobe dissipated, more frequency watts may be dissipated across the givencooling arrangement (e.g., heat sink), and there may be achieved ahigher frequency IC.

As to a possible further downstream increase in profits, if less heat isgenerated, less has to be dissipated by the cooling arrangement (at thesame frequency). If less cooling is required, then a lower cost coolingarrangement may be able to be implemented (with the same frequency),resulting in higher profits for a boxed IC manufacturer or assemblingOEM.

Discussions turn finally to a final FIG. 4 example. More particularly,FIG. 4 is a third (advantageous) example testing flow and yieldarrangement (embodiment) 400 useful in gaining furtherunderstanding/appreciation of the present invention. While the FIGS. 1–3example embodiments focused on testing on a basis of power specs, FIG. 4focuses on another example alternative that instead focuses on testingon a basis of IC reliability.

More particularly, ICs are sometimes bin-sorted/valued/sold on a basisof reliability specs as opposed to power specs. Thus, FIG. 4 isconcerned with testing according to the above mentioned reliabilityequation, i.e.:Rel=f(Vcc, Temp, V _(t) ,L _(min))  (Eq. 3)Note that just like the previously used Fmax equation, Vcc is a viableparameter to vary at testing time In an attempt to improve pass-ability,yield and profit in the testing of an IC batch.

As a prelude to the reliability testing, predetermined testing voltagelevel steps and reliability specs may be determined which might beappropriate to apply to the ICs. Such is shown representatively by theFIG. 4 block 435. For sake of consistency with other examples/FIGs., inthe present FIG. 4 example arrangement, it is again assumed that it isappropriate to test between 1.50V and 1.75V in 25 mV steps.

As to determination of appropriate reliability specs, since asubstantial portion of any IC's internal design/workings typically ismaintained as a trade secret, again, determination of appropriate steptarget voltages and reliability specs for reliability testing is mosteasily/appropriately determinable by those skilled in the art who aremost intimately involved with the internal design/workings of that IC,and is well within the purview of such skilled artisans. As onenon-limiting, non-exhaustive example, a reliability spec/determinationmay look at a number of expected hours before IC failure is expected tooccur. It should also be noted that similar to the FIGS. 2–3 examples,testing with the present FIG. 4 example may also require a differingreliability spec for each respective step target voltage.

Upon testing, if a FIG. 4 IC being tested at a step target voltagedisplays reliability within the ranges of its corresponding reliabilityspec, then the IC may be considered a “PASS” for the given step targetvoltage and reliability spec. Alternatively, if outside of range duringtesting, then the IC may be considered a “FAIL”.

FIG. 4 is substantially similar to FIG. 3 except for the reliabilityspec determination (block 435), reliability testings (blocks 440–449),and corresponding bin distributions according to reliability pass andfail (arrows 460–465, 470–475, 490–495, 499). Accordingly, redundantdiscussion thereof is omitted for sake of brevity. Testing is againconducted from lowest step voltage to highest to again take advantage ofthe fact that such testing hierarchy tends to pass/distribute ICs intothe lowest (i.e., the most commercially valuable) step (Vcc) voltage.

Similarly, reliability testing is conducted at each step voltage fromgreatest reliability to lowest to likewise take advantage of the factthat it tends to pass/distribute ICs into FIG. 4's leftmost (mostcommercially valuable) reliability commercially valuable) bin. That is,the FIG. 4 bins are arranged such that the left-most bin has the highestreliability (most commercial value), whereas the rightward bins havelower and lower reliability (and less and less commercial value).

At the conclusion of testing, there may be an example bin splitdistribution of the ICs within the bins as shown in parenthesis at thebottom of FIG. 4. That is, while the FIG. 3 example had shown examplefrequency bin distributions of: BIN1 (6.7%), BIN2 (35.9%), BIN3 (42.1%),BIN4 (14.4%), BIN5 (0.5%), DISCARD (0.4%), FIG. 4 shows reliability bindistributions of BIN1 (11.4%), BIN2 (48.8%), BIN3 (36.6%), BIN4 (2.8%),BIN5 (0.0%), DISCARD (0.4%).

While FIGS. 2–4 shows optimization on a basis of a minimum passingsupply voltage, verses maximum frequency or maximum reliability(respectively), practice of embodiments of the present invention is notlimited thereto. More particularly, as additionalnon-limiting/non-exhaustive examples, improved testing embodiments mayalso or alternatively perform predetermined optimization on a basis of:a maximum passing supply voltage level; a passing supply voltage levelexpected to provide a greatest reliability of the IC; a passing supplyvoltage level expected to provide a longest operational life for the IC;a passing supply voltage level providing a maximized reliableoperational frequency of the IC; a passing supply voltage levelproviding minimized power consumption by the IC; a passing supplyvoltage level providing minimized heat generation by the IC; a passingsupply voltage level providing maximized financial profit for the IC;constant total power; constant total reliability.

Practice of embodiments of the present invention is not limited to theexact flow sequence shown/described in FIGS. 2–4 and 6. For example, anIC may be tested at a single predetermined voltage to find a PASSABLEfrequency, and then located to the PASSABLE frequency and retestedthrough ones of the stepped voltages in an attempt to optimize the PASSvoltage.

Further, practice of embodiments of the present invention is not limitedto testing according to stepped voltages. As one non-exhaustive example,it may be possible to test a part at a predetermined single test voltage(e.g., a high Vcc), and measure predetermined parameters (e.g., the maxfrequency, power and leakage), and then, using a formula based on aprocess model, calculate a workable (pass) or even optimal operationvoltage for that part (for a specific bin and power limit) withouttrying to test the part in different step test voltages. To verifycalculations and the part operation, the part may then be tested at thecalculated Vcc and frequency. As to determination of an appropriateformula, since a substantial portion of any IC's internaldesign/workings typically is maintained as a trade secret, again,determination of a workable formula is most easily/appropriatelydeterminable by those skilled in the art who are most intimatelyinvolved with the internal design/workings of that IC, and is wellwithin the purview of such skilled artisans.

As a result of all of the foregoing, it can be seen from any of FIGS.2–4 that an example embodiment of the present invention is viewable asan inventory of same-batch/same-type ICs having diversely designatedoperating (Vcc) voltages and/or thermal resistances, and/or diverselydesignated internal VID voltages programmed therein.

At least a portion (if not all) of the present invention may bepracticed as a software invention (e.g., a testing program), implementedin the form of at least one sequence of instructions embodied in atleast one machine-readable medium and/or in data signals existing on atleast one data signal conductor. The sequence of instructions, whenexecuted, causes a machine (e.g., a testing machine) to effectoperations with respect to the invention. With respect to the term“machine”, such term should be construed broadly as encompassing alltypes of machines, e.g., a non-exhaustive listing including: computingmachines, non-computing machines, processing machines, communicationmachines, etc. “Machine-readable medium” includes any physical mediumthat provides (i.e., stores and/or transmits) information in a formreadable by a machine, and should be broadly interpreted as encompassinga broad spectrum of mediums, e.g., electronic medium (read-only memories(ROM), random access memories (RAM), flash cards); magnetic medium(floppy disks, hard disks, magnetic tape, etc.); optical medium(CD-ROMs, DVD-ROMs, etc). “At least one” associated with“machine-readable medium” means that ones of the sequence ofinstructions may be distributed across diversely-typed and/orgeographically displaced mediums.

“Data signals” includes any type of signal that provides (i.e., storesand/or transmits) therein, information in a form readable by a machine,and should be broadly interpreted as encompassing any one or combinationof a broad spectrum of signal types, e.g., a non-exhaustive listingincluding: electrical, optical, acoustical, digital, analog, or otherform of propagated signals, etc. “Data signal conductor” includes anyviable conductor, e.g., conductive wires, optical (e.g., fiber optic)wires, antennas, etc. “At least one” associated with “data signalconductor” means that ones of the sequence of instructions may bedistributed across diversely-typed and/or geographically-displacedconductors.

In concluding, reference in the specification to “one embodiment”, “anembodiment”, “example embodiment”, etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment or component, it is submitted that it iswithin the purview of one skilled in the art to effect such feature,structure, or characteristic in connection with other ones of theembodiments or components. Furthermore, for ease of understanding,certain method procedures may have been delineated as separateprocedures; however, these separately delineated procedures should notbe construed as necessarily order dependent in their performance, i.e.,some procedures may be able to be performed: in an alternative ordering;simultaneously; partially overlapping; etc.

This concludes the description of the example embodiments. Although thepresent invention has been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis invention. More particularly, reasonable variations andmodifications are possible in the component parts and/or arrangements ofthe subject combination arrangement within the scope of the foregoingdisclosure, the drawings and the appended claims without departing fromthe spirit of the invention. In addition to variations and modificationsin the component parts and/or arrangements, alternative uses will alsobe apparent to those skilled in the art.

Non-exhaustive examples of changes/alternatives are given as follows.For example, while testing at 25 mV steps was selected for the steptarget voltages for the above example embodiments, practice ofembodiments of the present invention are by no means limited thereto. Infact, finer granularities (e.g., 12.5 mV) of testing voltage level stepsmay result in more optimal distributions, and thus, even greateryield/profit/etc. As another example, the above FIGS. 2–4 embodimentsstop the testing of an IC immediately upon the occurrence of a firstPASS during testing. In contrast, a scope of the present invention mayinclude embodiments which do not immediately pass ICs upon a first PASS,but instead test each ICs at all testing steps to determine all PASSESbefore deciding into which bin an IC should be distributed. Thus, an ICthat might be a borderline pass in one bin, might instead be able to bedesignated into a bin in which it is a solid pass. Alternatively, if anIC is a pass for multiple bins, it might be able to be designated intothe bin that has the lowest inventory.

1. A method comprising: testing an integrated circuit (IC) of amanufacturing batch of ICs having a mutually-common design, for aplurality of predetermined voltage level steps determined for the batch;passing the IC if predetermined operational parameters are met for atleast one voltage level step; and in response to the passing,associating the IC with designated voltage level information identifyinga designated voltage level based on the at least one voltage level step,the designated voltage level information accessible by an automaticpower supply for automatic self-selection of the designated voltagelevel for the IC.
 2. A method as claimed in claim 1, wherein thedesignated voltage level information is at least one of: open circuitlevels on a plurality of voltage identifier (VID) connections of the IC;short circuit levels on the plurality of VID connections of the IC;electrical signal information transmissible from the IC; opticallyreadable information on the IC; magnetically readable information on theIC; electromagnetic transmission information transmissible from the IC;and database information retrievable remotely from the IC.
 3. A methodas claimed in claim 1, wherein the automatic power supply is a voltageregulator module (VRM) capable of gaining awareness of the designatedvoltage level information of the IC.
 4. A machine-readable medium havingstored thereon a set of instructions that, when executed, causes amachine to perform a method comprising: testing an integrated circuit(IC) of a manufacturing batch of ICs having a mutually-common design,for predetermined voltage level steps determined for the batch; passingthe IC if predetermined operational parameters are met for at least onevoltage level step; and in response to the passing, associating the ICwith designated voltage level information identifying a designatedvoltage level based on the at least one voltage level step, thedesignated voltage level information accessible by an automatic powersupply for automatic self-selection of the designated voltage level forthe IC.
 5. The medium as claimed in claim 4, wherein the designatedvoltage level information is at least one of: open circuit levels on aplurality of voltage identifier (VID) connections of the IC; shortcircuit levels on the plurality of VID connections of the IC: electricalsignal information transmissible from the IC; optically readableinformation on the IC; magnetically readable information on the IC;electromagnetic transmission information transmissible from the IC; anddatabase information retrievable remotely from the IC.
 6. The medium asclaimed in claim 4, wherein the automatic power supply is a voltageregulator module (VRM) capable of gaining awareness of the designatedvoltage level information of the IC.
 7. A method of manufacturingcomprising: manufacturing a batch of integrated circuits (ICs) having amutually-common design; testing individual ICs in the batch using apredetermined supply voltage level determined for the batch, passingindividual ICs in the batch which meet predetermined operationalparameters and designating such passed ICs to be operated at the supplyvoltage level; and in response to failure of an individual non-passed ICto operate within the predetermined operational parameters at the supplyvoltage level at each of a plurality of predetermined frequencies,retesting individual non-passed ICs using a differing supply voltagelevel, passing individual retested ICs which meet the predeterminedoperational parameters and designating such retested and passed ICs tobe operated at the differing supply voltage level which met thepredetermined operational parameters.
 8. A method as claimed in claim 7,wherein retesting is conducted at a plurality of differing supplyvoltage levels.
 9. A method as claimed in claim 7, wherein saiddesignating comprises associating each passed IC with designated voltagelevel information identifying a designated voltage level based on acorresponding supply voltage level, the designated voltage levelinformation accessible by an automatic power supply for automaticself-selection of the designated voltage level.
 10. A method as claimedin claim 9, wherein associating each passed IC with designated voltagelevel information comprises electrically setting an internal voltageidentification arrangement.
 11. A method as claimed in claim 10, whereinelectrically setting an internal voltage identification arrangementcomprises blowing an internal electrical fuse.
 12. A method comprising:testing sequentially integrated circuits (ICs) of a manufacturing batchof ICs having a mutually-common design for a plurality of predeterminedvoltage level steps determined for the batch, wherein each tested IC istested at at least two voltage level steps; retesting an IC at a highervoltage level step in response to failure of the IC to operate within apower specification associated with a lower voltage level step at eachof a plurality of predetermined frequencies; passing the IC ifpredetermined operational parameters are met for at least one voltagelevel step; and designating an IC having a plurality of passing voltagelevel steps to be operated at one of the plurality of passing voltagelevel steps based on a predetermined optimization.
 13. A methodcomprising: testing sequentially integrated circuits (ICs) of amanufacturing batch of ICs having a mutually-common design for aplurality of predetermined voltage level steps determined for the batch,wherein the testing tests each IC at a predetermined test voltage tomeasure predetermined parameters and applies the measured parameters toa predetermined formula based on a process model to determine at least apassable voltage level for the IC; retesting an IC at a higher voltagelevel step in response to failure of the IC to operate within a powerspecification associated with a lower voltage level step at each of aplurality of predetermined frequencies; and passing the IC ifpredetermined operational parameters are met for at least one voltagelevel step.
 14. A machine-readable medium embodying at least onesequence of instructions that, when executed, causes a machine to: testintegrated circuits (ICs) of a manufacturing batch of ICs having amutually-common design for predetermined voltage level steps determinedfor the batch, wherein each test IC is tested at at least two voltagelevel steps; retesting an IC at a higher voltage level step in responseto failure of the IC to operate within a power specification associatedwith a lower voltage level step at each of a plurality of predeterminedfrequencies; pass the IC if predetermined operational parameters are metfor at least one voltage level step; and designate an IC having aplurality of passing voltage level steps to be operated at one of theplurality of passing voltage level steps based on a predeterminedoptimization.